Valve Lash - Hot or cold?

You can set them cold but you'll have to set them hot, first, to get a baseline

EOIC Which means as the EXHAUST is starting to OPEN, adjust that intake, and as the INTAKE has opened fully and is nearly CLOSED, adjust that exhaust

Adjust them carefully, engine stopped, as above, HOT. Install covers, warm it up again, RECHECK. Make CERTAIN they are where you want them to be and NOTE that setting

Now let the engine cool FULLY, like, maybe, overnight. Now pull the covers, COLD, and carefully document the settings, average them out, etc, and this will be your COLD setting to obtain the correct HOT setting.